7 research outputs found

    Specificity of Tissue Transglutaminase Explains Cereal Toxicity in Celiac Disease

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    Celiac disease is caused by a selective lack of T cell tolerance for gluten. It is known that the enzyme tissue transglutaminase (tTG) is involved in the generation of T cell stimulatory gluten peptides through deamidation of glutamine, the most abundant amino acid in gluten. Only particular glutamine residues, however, are modified by tTG. Here we provide evidence that the spacing between glutamine and proline, the second most abundant amino acid in gluten, plays an essential role in the specificity of deamidation. On the basis of this, algorithms were designed and used to successfully predict novel T cell stimulatory peptides in gluten. Strikingly, these algorithms identified many similar peptides in the gluten-like hordeins from barley and secalins from rye but not in the avenins from oats. The avenins contain significantly lower percentages of proline residues, which offers a likely explanation for the lack of toxicity of oats. Thus, the unique amino acid composition of gluten and related proteins in barley and rye favors the generation of toxic T cell stimulatory gluten peptides by tTG. This provides a rationale for the observation that celiac disease patients are intolerant to these cereal proteins but not to other common food proteins

    Comparison of methods generating antibody-epitope conjugates for targeting cancer with virus-specific T cells

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    Therapeutic antibody-epitope conjugates (AECs) are promising new modalities to deliver immunogenic epitopes and redirect virus-specific T-cell activity to cancer cells. Nevertheless, many aspects of these antibody conjugates require optimization to increase their efficacy. Here we evaluated different strategies to conjugate an EBV epitope (YVL/A2) preceded by a protease cleavage site to the antibodies cetuximab and trastuzumab. Three approaches were taken: chemical conjugation (i.e. a thiol-maleimide reaction) to reduced cysteine side chains, heavy chain C-terminal enzymatic conjugation using sortase A, and genetic fusions, to the heavy chain (HC) C-terminus. All three conjugates were capable of T-cell activation and target-cell killing via proteolytic release of the EBV epitope and expression of the antibody target was a requirement for T-cell activation. Moreover, AECs generated with a second immunogenic epitope derived from CMV (NLV/A2) were able to deliver and redirect CMV specific T-cells, in which the amino sequence of the attached peptide appeared to influence the efficiency of epitope delivery. Therefore, screening of multiple protease cleavage sites and epitopes attached to the antibody is necessary. Taken together, our data demonstrated that multiple AECs could sensitize cancer cells to virus-specific T cells.Bio-organic Synthesi
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